docs: Increase discoverability of functions and articles

[gadenbuie]

• Bring the @family tag to more places.
• More @seealso in more places.
• @seealso follow the style of complete sentences, typically X {verb} {description}. E.g. [card()] creates a card component. is used in the ?card_body docs.
• @family Components is applied to the primary component function, e.g. card(), but not the secondary functions, e.g. card_body(). In the docs it will read Other components: card(), ... and these secondary functions reduce legibility.
• In @references I'm trying to link to all relevant articles on the bslib website for each component.
• Prefer rlang::is_interactive() over interactive() in examples, and try to use @examplesIf rlang::is_interactive() as much as possible.